1. Field of the Invention
The present invention relates to work table apparatus for a plate material processing machine such as a press forming machine, and more specifically to a work table apparatus for a plate; material processing machine which can support a plate material to be processed so as to be movable in one axis direction of coordinates.
2. Description of the Prior Art
In plate material processing machines such as press forming machines, there exists a work movement type such that a work plate material is shifted in one axis direction of coordinates along a work pass line by use of a work carriage, for instance to a predetermined position at which a press processing section composed of a pair of punch and die, for instance are arranged to process the work plate material.
In the plate material processing machine of the type as described above, the work table apparatus is so constructed as to support a work plate material at a work pass line height and further to shift the supported work plate material in one axis direction of the coordinates. In general, the work table apparatus as described above is constructed as a completely fixed work table or a partially fixed work table (such as a center table of a turret disk punch press, for instance) so as to prevent the interference between the table members and the plate material processing section, and a work plate material to be processed is slidably supported on a plurality of free bearings arranged on the Work table surface extending along the work pass line.
In the above-mentioned plate material supporting method by the prior art work table apparatus, however, since the work plate material is supported at point contacts by the free bearings, there exist various problems in that some microjoint portions of punched products (for supporting punched products so as not to be removed from the processed plate material) are caught by the free bearings and therefore removed from the processed plate material, and further the punched products of small dimensions drop passing through between the bearings, thus there inevitably exists a lower limit of the dimensions of the products to be punched. In addition, when the plate material to be processed is slid on and along the free bearings, there arise other problems in that the plate material is damaged by scratches and sound noise is inevitably produced.
Further, in the prior art work table apparatus, since the plate material to be processed is slid on and along the work table surface, the lower surface of the plate material to be supported by the work table should be flat without being formed with any downward projecting portions; that is, it has been impossible to process the work plate material so as to be formed with projections extending in the downward direction, for instance such as in the case of burring formation, lance formation, louver formation, etc.
Further, in the case of a fixed work table, an up-down mechanism is inevitably required to prevent interference of the work table members with work clamping members and an override detecting member.
Further, in the prior art work table for a plate material processing machine, a some gap exists between the work table surface and the free bearing surface, there arises a problem in that the plate material is curved downward when a great number of holes are formed simultaneously, thus deteriorating the processing precision or destroying the microjoint portions of the processed plate material.